To determine if treatment with HOE642 will reduce the amount of risk of heart damage and also reduce the number of fatal outcomes. Three groups of patients will be studied: 1) chest pain, 2) scheduled for coronary artery dilatation, 3) scheduled for coronary artery bypass. None of the patient's medications will be stopped. Subjects will be randomized to receive HOE642 20, 80mg or 120mg or placebo. Prior to the infusion and during the infusion vital signs and several samples of blood and urine will be taken